Random crap with Uno.

[Buster's Uncle]

My first impulse is naturally laminated latex with lots of cheesecloth or at least tissue, worked in for stiffness - if you don't think a lot of extra support will be need to fight bulging, or can easily be improvised on your end, I really don't want to fool with the plaster bracing.  If I wanted to pay for mailing several pounds of plaster, I'd just send you a good casting.

[Unorthodox]

Yeah, it don't take a whole heck of a lot.  My molds are usually 4 layers of latex, one has the cheese cloth in it.  3-4 layers of plaster on the cast.  Rough "human" sized plaster needed per layer is 1 cup dry plaster.  That should leave just a touch extra, which can be left in to reinforce one area (different area each layer).  The one thing to do if you do find it deform just a tad is put the mold in a bowl to dry that first layer of the cast.  Sometimes a flat survace is too much pressure on one area, spread that out a touch with small bowl for that first layer and they're fine. 

[Buster's Uncle]

I was just worried that the technique I use works just fine on small things, and I know what I'm doing there, but I've never done a latex cast on something as big as a whole head.  Even on the small things, bulging can be a problem if you do no bracing, though at fist-sized, a few layers of aluminum foil squeezed around it will do.  Wire mesh, like they sell at craft stores for such purposes, pressed into the right shape works too, with faces.  I use that sometimes for baking sculpey that doen't have a flat side to lay on.

[Unorthodox]

Sounds like you use fewer layers of latex for the small things. 

1 thin coat to start, 3 THICK coats following (and cheese cloth), you get a tough little mold. 

The biggest trick to these is removal. 

You do not want the cheese cloth in any undercuts, or the back of the head.

remove by rolling from the back, leaving the face for last.

[Unorthodox]

http://www.halloweenforum.com/tutorials-step-step/67547-glove-mold-making-101-a.html

[Buster's Uncle]

I go pretty thick, actually, and more than four layers - but when you pour water into a bag, the bag wants to get very round.

[Unorthodox]

See, that's a solid pour, though.  Here, your pouring 1 cup of plaster (into a roughly quart sized cavity), and coating the mold evenly. 

Perhaps the trickiest part is how fragile that first layer is, but I've always considered cracks and breaks in it to be a bonus. 

[Buster's Uncle]

That makes sense.

I'd been considering an alumninum foil core, so I could do a solid casting...

[Buster's Uncle]

I wish all the pictures displayed at that link...

[Unorthodox]

Yeah, that is the reason I abandoned imageshack.  Some of those are irrecoverable. 

[Buster's Uncle]

...I've only just now finished reading that thread and the crystal skull one.  I hate working in resin...

[Buster's Uncle]

No opinion about trying a light core to make a solid pour?

[Unorthodox]

That's not something I'm experienced that with.  And it was a PAIN in the ass to get to work properly.  You would definitely need a mother mold

I could ask if scourge (owns that skullshoppe linked to above) wants to come comment, he used to do injection molding, and we prototyped out some molds to learn the ins and outs of it back in the day, but even he's moved away from that kind of thing and does his (resin) molds in an automated shell system like I do the plaster, just has a machine to constantly rotate the molds till the resin cures.

[Buster's Uncle]

Eh, if it's a bigger pain than what I'm already proposing to put myself up against, maybe I'm not interested.  Otherwise, I'd be all over that crystal skull thing - if you could get the process down to getting a smooth, polished result, it would be pretty mind-blowing.

But resin?  Meh.  The stuff is of the devil.  Expensive, dangerous, spotty results for no discernible reason, and just plain nasty to work with.

[Unorthodox]

OH, the crystal skull smooth?

Yeah, we have that down pretty well.  It was not a smooth original, to begin with. 

lessee...think that was 2008. 

This one is from a wood carving original and you can still see the wood grains on it, that's why it's not "smooth". 



The trouble is in the fantastic weight and cost of making one of them. 

For the lindberg model there was the additional problem we couldn't do it as one pour because I underestimated the amount of resin it was going to take, and we were running into some serious temperature problems as a result. 

I've seen an RTV resin that's clear, but never tried it.